EuroPRevent: Trans Fat in Dairy and Beef Not Benign

Action Points

Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

Explain that small amounts of naturally occurring trans fats in milk and beef may increase the risk of death from cardiovascular disease.

Note that no significant association of partially hydrogenated vegetable oil, found in industrially processed products like margarine and shortening, was seen with deaths from cardiovascular disease (CVD) or coronary heart disease (CHD).

GENEVA -- Small amounts of naturally occurring trans fats in milk and beef boost cardiac risk more than expected, according to data from a large Norwegian population study.

Higher intake of these ruminant trans-fatty acids was consistently linked to greater risk of death from coronary heart disease and cardiovascular disease (P=0.05 to P=0.002 for trend) in the study of more than 71,000 people followed for around 25 years.

Trans fats from partially hydrogenated vegetable oils appeared to have been less risky, Ida Laake, a PhD student at the University of Oslo, Norway, and colleagues reported here at the European Society of Cardiology's EuroPRevent meeting.

No significant association of partially hydrogenated vegetable oil, found in industrially processed products like margarine and shortening, was seen with deaths from cardiovascular disease (CVD) or coronary heart disease (CHD) in the cohort.

Laake called the magnitude of the ruminant trans fat risk surprising, noting that some have claimed intake is too low to have any consequences.

"Maybe they're not as harmless as previously thought," she told MedPage Today in an interview.

She didn't recommend that people cut down on dairy or beef intake based on the results of a single study, but pointed out at the session that lower-fat products contain proportionately less trans fat.

Her group's study included nearly 36,000 men and more than 35,000 women, ages 35 to 49, from three Norwegian counties, who were screened three times from 1974 through 1988 with a semi-quantitative food frequency questionnaire, and followed for cardiovascular outcomes through 2007 via national registries.

All results were adjusted for age, body mass index, smoking, education level, triglycerides, systolic blood pressure, and total caloric intake as well as intakes of saturated fat, carbohydrate, protein, cholesterol, and all trans fatty acids.

Men with the highest consumption of ruminant trans fats were 21% more likely to die from CVD (hazard ratio 1.21, 95% confidence interval 0.96 to 1.51) and 41% more likely to die from CHD (HR 1.41, 95% CI 1.07 to 1.86) than those with the lowest intake.

Women with the highest ruminant trans fat intake were 61% more likely to die from CVD (HR 1.61, 95% CI 1.07 to 2.43) and nearly twice as likely to die from CHD (HR 1.95, 95% CI 1.08 to 3.52) compared with those in the lowest intake category.

Trans fat from partially hydrogenated vegetable oil showed only a trend for harm with coronary heart disease deaths in men (P=0.06 for trend with intake as a continuous variable).

Trans fat from partially hydrogenated fish oil was associated with more risk (P=0.01 to P=0.002 for trend as a continuous variable). Hazard ratios with the highest versus lowest intake were as follows:

1.27 for CVD death in men (95% CI 1.06 to 1.52)

1.32 for CHD death in men (95% CI 1.05 to 1.66)

1.39 for CVD death in women (95% CI 1.03 to 1.86)

1.42 for CHD death in women (95% CI 0.93 to 2.17)

Partially-hydrogenated fish oil, produced with an industrial process from liquid fish oil, was never popular in the U.S. and stopped being manufactured in Europe in around 2003, Laake noted.

A comeback is unlikely, but the concern is the contribution they've already made to heart disease, she told MedPage Today.

"They were very common," she said in an interview. "They've been consumed in considerable amounts in countries like Norway, the Netherlands, Great Britain."

Her group concluded that the risks from all these types of trans fats "may be explained by the unfavorable effects of these fatty acids on plasma lipoproteins."

Laake noted that the intake of partially hydrogenated fish oils was probably higher in Norway in the period studied than in other countries but didn't have comparisons for the other trans fat sources.

Session moderator Marco Guazzi, MD, PhD, of the Institute of Cardiology in Milan, Italy, added the caution that the study should have adjusted for diastolic rather than systolic blood pressure for a younger adult population.

Laake reported having no conflicts of interest to disclose. One co-author reported being on a board for the food company Mills, and one reported conflicts with Nofima Food.

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